Fig. 1.

C57BL/6J mice consumed more kilocalories and gained weight in the first 7 days of high-fat feeding. A and B: mice given high-fat diet (HFD) ate fewer grams of chow per day (A), which nonetheless translated to more kilocalories per day (B) than mice fed control chow (CD) (n = 51–53). C: young adult mice fed CD gained a small amount of body weight over the 7-day intervention, whereas mice fed HFD gained weight as early as day 3, with a 10% weight gain by day 7 (n = 59–60). D: testicular fat pad mass was doubled on day 7 in mice fed HFD (n = 6–7). Data are expressed as means ± SE; P values were calculated by Student's t-test (A, B, D) or ANOVA (C). *P < 0.05, **P < 0.01, ****P < 0.0001; ns, nonsignificant.